1. Field of the Invention
The present invention relates to an apparatus and a method for manufacturing an optical disk, an apparatus and a method for recording data on the optical disk, and an apparatus and a method for reproducing data from the optical disk, as well as the optical disk. For example, the present invention can apply to a compact disk, a compact disk player, an optical disk for recording audio data, and a recording apparatus and a reproducing apparatus usable for the optical disk.
The present invention changes the reflectance of the optical disk locally, thereby giving a jitter to the positional information of each pit edge, so that desired data is recorded on the optical disk additionally. Consequently, various data can be recorded on the optical disk so as to be reproduced by an optical pickup for reproducing data strings and not to be copied illegally without any adverse effect on the reproduction of the data strings recorded in the from of pit strings.
In addition, the present invention deviates bits, etc. towards the inner/outer region of the optical disk, thereby recording such subdata as key information, etc., so that various data can be recorded on the optical disk so as to be reproduced by an optical pickup for reproducing the data strings and not to be copied illegally without any adverse effect on the reproduction of the data strings recorded in the form of pit strings.
2. Description of the Related Art
In the case of conventional compact disks (CD), data strings to be recorded have been processed, then subjected to EFM modulation (Eight to Fourteen Modulation), thereby such data as audio data is recorded.
On the other hand, a management data recording area is formed in the lead-in area provided in the inner region of the optical disk and the TOC (Table Of Contents) recorded in this recording area is used to selectively reproduce desired musical performance data, etc.
A compact disk having various recorded data as described above is provided with a recording area for the IFPI (International Federation of the Photographic Industry) code in an inner area of the lead-in area, where such signals as audio signals and the TOC (Table Of Contents) used by the object user are recorded. This area also has such inscription codes as factory name, the disk number, etc., with which the history of the compact disk can be checked visually.
By the way, such the inscription data as a maker name, a factory name, a disk number, etc. are enscrolled on each compact disk so that the history of the compact disk is checked visually and such the inscription data is used for discriminating illegally copied disks manufactured from an original disk. However, because such the inscription data is recorded so as to be checked visually, the inscription data arises a problem that the data cannot be reproduced easily by an optical pickup of the compact disk player. In order to solve this problem, therefore, a reproducing mechanism is required dedicatedly for reproducing the inscription data while it is enabled to discriminate this inscription data from illegally copied disks.
The inscription data to be recorded with those methods is recorded in the form of pits ordinarily and checked visually, if it can be duplicated by, for example, creating a stamper by peeling both protection film and aluminum reflection film from the object compact disk. And, this is why the compact disk cannot be protected from illegal copying.
To solve the above-mentioned problems, for example, Japanese Patent Laid-Open No.9-67843 discloses a method in which the output of a recording laser is varied to change the pit width recorded on the disk, thereby recording the inherent code on the disk.
For example, as the first example, there is a well-known method in which a recording signal on a disk is encrypted and key information for decryption is recorded as a variation of the pit width according to the method described in the above-mentioned patent application. A reproducing apparatus is composed so that the key information recorded as described above is detected and the cryptogram is decrypted according to the detected key information. Because the key information is not recorded on the pirated disk, the cryptogram is therefore not decrypted and the content of the disk is not reproduced normally. Therefore, if a reproducing apparatus is composed as described above, then the pirated disk becomes useless, thereby the pirated copy is substantially prevented.
Now, there are two well-known methods for making a pirated disk; a method in which reproduced signal from a disk is supplied to a recording unit as is and the other method in which the physical configuration of a disk is transferred as is. If a disk which is manufactured according to the above-mentioned first example is used for making a pirated disk according to the method in which the reproduced signal is supplied to a recording unit as is, then the key information recorded in the form of pit width change is not recorded on the pirated disk though the information recorded in the form of xe2x80x9cpit/no pitxe2x80x9d change is recorded in the pirated disk. Therefore it is possible to prevent making of a pirated disk according to the method in which the reproduced signal is supplied to a recording unit as is by employing the method described in the first example. However, if a disk which is manufactured according the above-mentioned first example is used for making a pirated disk according to the method in which the physical configuration of a disk is transferred, then the key information recorded in the form of pit width change is also copied to a pirated disk. Therefore, the first example method is disadvantageous in that making of a pirated disk according to physical transfer can not be prevented.
Now, the second example is known as a method for solving such a problem. In the second example, the key information is recorded not in the form of physical configuration but in the form of reflectance change. In detail, a groove is formed on an area such as the lead-out area of an optical disk, an intensive laser beam is irradiated onto the reflection film of this area, thereby changing the reflection characteristic, and the same information as that of a bit string is recorded.
If the key information is recorded in the form of reflectance change, the key information is recorded in the form of reflection characteristic change of a reflection film. Because the key information is not recorded in the form of physical configuration (pit), the key information will not be copied on the pirated disk which is made according to physical transfer. Therefore, this method complements the disadvantage of the first example, and it is possible to prevent the making of the pirated disk by the use of the method according to physical transfer.
However, the second example is also disadvantageous in that if a pirated disk is made according to the method in which the reproduced signal is supplied to a recording unit as is, the key information recorded on the lead-out area is copied as is.
As described above, the respective methods for preventing the pirated disk which is proposed are effective only on either of the two methods for making a pirated disk herein addressed. Furthermore, if a pirated optical disk is made according to a method not described above, these methods are entirely not effective.
Under such the circumstances, it is an object of the present invention to provide an apparatus and a method for manufacturing an optical disk from which no pirated optical disk can be produced by any of a method in which the reproduced signal is supplied directly to a recording unit and a method in which the configuration of the optical disk is transferred physically, thereby eliminating the disadvantage of the conventional pirated copying method, and an optical disk to which such pirated copy prevention is applied and a method for reproducing an optical disk to which such pirated copy prevention is applied.
Besides that, it will also be possible to reject an illegal copy with the use of this data if various data can be recorded so as to be reproduced with an optical pickup for reproducing audio data and to be difficult to copy illegally without any adverse effect on the reproduction of audio data as pit strings.
It is therefore another object of the present invention to provide an optical disk, an optical disk recording unit, an optical disk recording method, an optical disk reproducing apparatus, and an optical disk reproducing method which can record various data for inhibiting illegal copying so as to be reproduced with an optical pickup for reproducing data recorded in the form of a pit string, etc. and to be difficult to copy illegally without any adverse effect on the reproduction of data recorded in the format of a pit string, etc.
In order to solve the above conventional problems, an optical disk manufacturing apparatus in accordance with the first present invention for manufacturing an optical disk having recorded digital data to be read out by irradiation of a laser beam comprises an encryption unit for encrypting input digital data according to a plurality of key information, an optical disk substrate manufacturing machine for manufacturing an optical disk substrate on which the encrypted digital data and the key information are recorded in the form of physical configurational change, a reflection film forming unit for forming a reflection film on the optical disk substrate, and a key information recording unit for recording the key information on the optical disk substrate having the reflection film thereon.
According to such the first present invention, the encryption unit encrypts input digital data according to a plurality of key information, the optical disk substrate manufacturing unit manufactures an optical disk substrate on which the encrypted digital data and key information are recorded in the form of physical configurational change, the reflection film forming unit forms a reflection film on the optical disk substrate, and the key information recording unit records the key information on the optical disk substrate on which the reflection film is formed.
The first present invention provides an optical disk manufacturing apparatus for manufacturing an optical disk having recorded digital data to be read out by irradiation of a laser beam comprising an encryption unit for encrypting input digital data according to a plurality of key information, an optical disk substrate manufacturing machine for manufacturing an optical disk substrate on which the encrypted digital data and the key information are recorded in the form of physical configurational change, a reflection film forming unit for forming a reflection film on the optical disk substrate, and a key information recording unit for recording the key information on the optical disk substrate having the reflection film thereon.
The second present invention provides the optical disk manufacturing apparatus described in claim 1, wherein the optical disk substrate manufacturing unit comprises an exposing unit for converging a laser beam on an optical disk according to the encrypted digital data and the key information to expose the optical master disk, a stamper forming unit for forming a stamper by applying a chemical treatment on the exposed optical master disk, thereby changing the physical configuration thereof, and a duplication unit for transferring the physical configurational change on the stamper, thereby generating a plurality of optical disk substrates.
The third present invention provides the optical disk manufacturing apparatus described in claim 2, wherein the exposing unit comprises a laser beam intensity modulation unit for modulating the intensity of the laser beam according to the encrypted digital data, and a laser beam convergent position changing unit for changing the convergent position of the laser beam according to the key information.
The fourth present invention provides the optical disk manufacturing apparatus described in claim 3, wherein the laser beam intensity changing unit comprises a modulation unit for generating a modulated signal according to the encrypted digital data, and an optical modulation unit for controlling the on/off of the laser beam according to the modulated signal.
The fifth present invention provides the optical disk manufacturing apparatus described in claim 1, wherein the key information recording unit comprises a laser beam generation unit for generating a laser beam, an optical intensity modulation unit for modulating the laser beam according to the key information, and a converging unit for converging and irradiating the modulated laser beam on a predetermined position on the optical disk.
The sixth present invention provides an optical disk manufacturing method for manufacturing an optical disk having recorded digital data to be read out by irradiating a laser beam comprising an encryption step for encrypting input digital data according to a plurality of key information, an optical disk substrate manufacturing step for manufacturing optical disk substrates on which the encrypted digital data and the key information are recorded in the form of physical configurational change, a reflection film forming step for forming a reflection film on the optical disk substrate, and a key information recording step for recording the key information on the optical disk substrate on which the reflection film is formed.
The seventh present invention provides the optical disk manufacturing method described in claim 6, wherein the optical disk substrate manufacturing step comprises an exposing step for converging a laser beam on an optical disk according to the encrypted digital data and the key information to expose the optical master disk, a stamper forming step for forming a stamper by applying a chemical treatment on the exposed optical master disk to change the physical configuration thereof, and a duplication step for transferring the physical configurational change on the stamper, thereby generating a plurality of optical disk substrates.
The eighth present invention provides the optical disk manufacturing method described in claim 6, wherein the key information recording step comprises a laser generating step for generating a laser beam, a modulation step for modulating the laser beam according to the key information, and a laser irradiation step for converging and irradiating the laser beam on the optical disk substrate.
The ninth present invention provides an optical disk having digital data recorded in the form of physical configurational change, which is composed so as to reproduce digital data by reflecting an incident laser beam from its reflection film, wherein the digital signal is encrypted according to a plurality of key information, one of the plurality of key information is recorded on the optical disk in the form of physical configurational change, and at least one of the plurality of key information is recorded in the form of reflectance change of the reflection film on the optical disk.
The tenth present invention provides an optical disk reproducing method for reproducing an optical disk having recorded encrypted digital data, wherein the method comprises the first reproducing step for reproducing the first key information recorded on the optical disk in the form of physical configurational change, the second reproducing step for reproducing the second key information recorded on the optical disk in the form of reflectance change, and a decryption step for reproducing the digital data recorded on the optical disk and decrypting the reproduced digital data by use of the first and second key information.
In the eleventh present invention applied to an optical disk apparatus or optical disk recording method, the beam intensity of a recording laser beam irradiated onto an optical disk is raised intermittently according to the edge detection result and the recording signal to locally change the reflectance of the optical disk, thereby the timing when the reflecting beam reception result crosses the predetermined reference level is changed.
In the present invention applied to an optical disk, the reflectance changes locally so that a jitter is given to the reflected beam reception result obtained by scanning the laser beam on pits or marks, and additional data is recorded according to the local reflectance change.
The beam intensity of the recording laser beam irradiated onto the optical disk is raised intermittently to locally change the reflectance of the optical disk and the timing when the reflected beam reception result crosses the predetermined reference level is changed, thereby the additional data is reproduced so that the optical disk is not copied illegally, the additional data such as disk discrimination code is recorded, and the additional data is reproduced by processing the reproduction signal for reproduction without any adverse effect on the reproduction of the data recorded in the form of pit or mark pattern.
In the present invention applied to an optical disk, the reflectance is locally changed so as to give a jitter to the reflected beam reception result obtained by scanning a laser beam on pits or marks, and the additional data is recorded according to the local reflectance change, thereby the additional data is reproduced so that the optical disk is not copied illegally, the additional data such as disk discrimination code is recorded, and the additional data is reproduced by processing the reproduction signal for reproduction without any adverse effect on the reproduction of the data recorded in the form of pit or mark pattern.
Furthermore, according to another present invention in accordance with claim 27 or 33, when applied to an optical disk apparatus or an optical disk recording method, the main modulation signal is generated according to the main data, and the laser beam is irradiated on the optical disk according to this main modulation signal, thereby forming a pit string or a mark string thereon and sub-data is generated according to the sub-data, thereby generating the sub-modulation signal and the irradiation point of the laser beam is deviated towards the inner/outer region of the optical disk according to this sub-modulation signal.
Furthermore, according to the present invention in accordance with claim 39, when applied to an optical disk, if the main data is recorded according to the length of a pit or mark and the interval between pits or marks along the track, then sub-data is recorded according to the deviation of the pit or mark towards the inner/outer region from the center of the track.
Furthermore, according to the present invention in accordance with claim 45, when applied to an optical disk apparatus, the deviation detection signal is output, then processed with reference to the reproduction signal, thereby reproducing the sub-data recorded in the form of a deviation of the pit or mark towards the inner/reference region of the optical disk with reference to the center of the track. The signal level of the deviation detection signal is changed according to the deviation of a pit or mark towards the inner/outer region of the optical disk from the center of the track.
According to the present invention in accordance with claim 49, when applied to an optical disk reproducing method, the main data recorded in the form of a pit string or a mark string is reproduced with the reflected beam of the laser beam irradiated on the optical disk and the recorded sub-data is reproduced in the form of a deviation of the pit or mark towards the inner/outer region from the center of the track with the same reflected laser beam.
According to the configuration of the optical disk apparatus in accordance with claim 27 or 33, if the main modulation signal is generated according to the main data and a pit string or a mark string is formed with the laser beam irradiated according to this main modulation signal, and the sub-modulation signal is generated according to sub-data and the irradiation point of the laser beam is deviated according to this sub-modulation signal towards the inner/outer region of the optical disk, then the sub-data can be recorded with the selection of this deviation in the inner/outer region so as not to disturb the reproduction of the main data recorded in the form of pits or marks. The sub-data can also be recorded so as to be prevented from illegal copying and reproduced with an optical pickup for reproducing the main data together with the assignment of various data for inhibiting illegal copying, etc.
According to the configuration of the optical disk in accordance with claim 39, if the main data is recorded according to the length of a pit or a mark and the interval between pits or marks along the track and sub-data is recorded in the form of a deviation of pits or marks towards the inner/outer region of the optical disk with reference to the center of the track, then the main data can be reproduced correctly with the selection of this deviation of the pit or mark towards the inner/outer region of the optical disk. In addition, the sub-data can be recorded so as to be difficult to copy illegally and to be reproduced with an optical pickup for reproducing the main data together with the assignment of various data for inhibiting illegal copying, etc.
Furthermore, according to the configuration of the optical disk reproducing apparatus in accordance with claim 45, if the deviation detection signal is output and processed with reference to the reproduction signal, thereby the recorded sub-data is reproduced according to the deviation of the pit or mark to the inner/outer region of the optical disk with reference to the center of the track, the main data recorded as a pit string or mark string can be reproduced from an optical disk composed as described above, as well as the sub-data recorded in the form of a deviation of pits or marks towards the inner/outer region of the optical disk can be reproduced from the same optical disk. The level of the deviation detection signal is changed according to the deviation of the pit or mark towards the inner/outer region of the optical disk with reference to the center of the track.
Furthermore, according to the configuration of the optical disk reproducing method, if the main data recorded in the form of a pit string or a mark string is reproduced with the reflected beam of the laser beam irradiated on the optical disk and the sub-data recorded in the form of a deviation of pits or marks towards the inner/outer region of the optical disk with reference to the center of the track is reproduced with the same reflected beam of the laser beam, then both main and sub-data can be reproduced from an optical disk having various recorded data for inhibiting illegal copying so as to be reproduced with an optical pickup for reproducing data recorded in the form of a pit string, etc. and to be difficult to copy illegally.